Spark plug



Feb. 25, 1930. GEQRGIAS 1,748,338

SPARK PLUG Filed Nov. 25, 1929 Patented Feb. ,25, 1930 UNITED STATES;

IBASJLCE J2 GEORGIAS, OF BOSTON, MASSACHUSETTS SPARK PLUG Application filed November 25, 1929. Serial No. 409,718,.

My invention relates to spark plugs for internal combustion engines.

An everpresent difliculty experienced with engines of this type is the tendency to im- 5 perfect combustion of the explosive gases an the consequent deposit of free carbon on-the terminals of the spark plugs. While this difliculty is often due to the spark, the carbon deposit from any cause results in coating the terminals of the spark plugs and still further interfering with free sparking;

From my experience I have found that the increased area of sparking surface which I provide, results in a more reliable spark and the practical elimination of carbon deposit. By meansof the demountable feature of my invention, I am enabled to .remove and thoroughly clean the terminals, and any film which may form on the terminals can thus be readily removed and free sparking maintained.

The obj ects of my invention are to provide a spark plug with increased sparking surface; one which shall have interchangeable terminals adapted for use withvaried ex plosive mixtures, or according to seasonal conditions; and one in which the relation of the terminals may be maintained.-

My invention consists in the novel form of the terminals, and in the means I employ for attaining the afore mentioned objects.

In the specification and claims, and the drawings forming a part thereof, I have described and illustrated a preferred form of my invention but may modify the device within the scope of the appended claims.

Referring to the drawings,

. Fig. 1 is an enlarged view of a spark plug embodying my invention, partially in section. Fig.2 is a reversed lan of the same.

Fi 3 is a plan of t eterminals and th spacing ring I use.

Fig. 4 is a fragment shown in. section, in

.ally.

tends the conductor C. Instead of continuing-the conductor to form the positive terminal, I form the end in suitable 'manner to be engaged by replaceable terminals, one

d method'being as shown at 10 to thread the end. On this end I attach the terminals to be presently described. The body A is recessed at 11, and grooved at 12, the former to receive an insulating ring 13, notched at 14, to engage arms formed on a positive terminal 15, threaded to engage the end 10 of the conductor 0.. The positive terminals I employ are of two varieties, one as shown at 15, the other at 16, Fig. 4.

Both are provided with a tapped .hub 17, which is slotted at 17' as shown in Fig. 3, the threaded end 10 being tapered and the tapped hubs being slotted to permit yieldin as the terminal is turned on the thread. The form 15 comprises a ring 18 connected to the hub by the arms 19, which are engaged by the notches 14 of the insulating ring 13. The terminal is thus positively positioned later- The other form of terminal, 16 .is formed with an extension-2O of the hub 17. These forms of positive terminal are interchangeable to be operable with the negative terminal which will nowbe described. This negative terminal is formed of the concentric rings 22, 23 which are connected by the arms 24 which are formed to permit the positive terminal 15 to extend downwardly inoperable relation with Hug 22. When the positive terminal 16 is employed it extends downwardly in operable relation with thering 23. The

negative terminal rings are split as at 25, and

the ring 22 is splrung into the groove 12, the expansion of t e rlng to normal insuring positive electric contact with the body A and a fixed relation with either form of positive terminal. In cold weather and with a lean mixture'of gases, Iemploy the'termi nal. 15;

as the jsparki'n area'of bot-h rings'18 and 22 is relatively arge. In' warm weatlrer or with a'rich mixture of gases, I employ the form of terminal 16 which extends inoperable relation'into the ring 23. In the usual form. of spark plug, one or both of the terminals are liable to bending which results in either a feeble spark, or no spark at all, and by the employment of the insulating ring 13, I overcome this difliculty as applying to the terminal 15, and may modify it to include functioning with the terminal 16, the form of which, however is such I believe, that it will not be required. A further advantage of my invention is the longer life of the" rings connected and attachable to the body of the spark plug; and interchangeable electrode tips attachable to the conductor and operable respectively with one or the other of the concentric rings to produce a spark.

2. In a spark plug having a body portion, an insulating member mounted therein, and a conductor supported therein and extending therethrough, an electrode formed with a pair of concentric connected rings, split to permit engagement with a seat therefor, formed in the body of the spark plug.

3. In a spark plug having a body portion, an insulated member mounted therein, and a conductor supported therein and extending therethrough, and an electrode formed with a pair 0 concentric rings connected and attachable to the body of the spark plug; interchangeable electrode tips attachable to the conductor and respectively operable with the outer or inner ring of the electrode to produce a spark.

4. A spark plug comprising in combination, a. body portion; an insulating member mounted therein; a conductor supported therein and extending therethrough; a negative electrode formed with a pair of concentric connected rings in electric contact with the body; interchangeable electrode tips attachable to the conductor and operable respectively with one or the other of the concentric rings of the negative conductor to produce a spark and an insulating member engaging the positive electrode and the body of the spark plug for the purpose of main taining the relation of the positive and negative electrodes. 1

BASILE J. .eEoReIAs. 

